Device for testing relative frictional characteristics of materials



1,772,415 DEvI'cE Fon TESTING RELATIVE FRIoTIoNAL cHARAcTERIsTIUsor'uATRIALs ug. 5, 1930. E. CARPENTER Filed sept. 1v, ll1927 2Sheets-Sheet 1 Aug. 5,y 1930. E. CARPENTERA DEVICE yFOR TESTING RELATIVEFRICTINAL CHARACTERISTICS OP IATERIALS Filed Sept. 1'7, 1927 2Sheets-Sheet 2 2 in degrees, or may be based on an arbitrarily selectedunit.

The test specimens, see F ig. 4, which may be in the form of flatrectangular pieces 28 of the materials t0 be tested preferably occuplyva correspondingly shapedlreeess 29 1n underside of weight elements 31.These weight elementsn. the present instance are Y provided with apassage 321111 which is mounted a bolt 33. "The ends'of'tlie"'passage 32respectively at the upper and lower surface of the block 31` arecountersunk to provide in one instance a recess for receptionofV nuts34l Vwhich hold the bolt place, and in the'other instance for receptionof a spring 35 Conon.v thepouter projecting ends of which are pivotallymounted the side links 38 offa mem'- ber comprising these side links,together with connecting rods 39, 41, vwhichjointhe cor.- respondingends of the links together'. 'The connecting rod 39 of this vmemberis-so positioned as to occupy a position overlying the tops of theblocks31 when the latter'are at 4the top ofthe inclinedplanepan'd'springs'@ `connected to the side pieces 11 and 12 andto the:forward ends of the links 38 resiliently hold the connecting rod v39againstthe tops of the blocks 31, as shown 'Figli Stops 43are`providedfor the links 38 `whichlinriit the downward movement of'V the forwardends vof the links, and when they blocks 31 are withdrawn hold theforward ends of thelinks in a positionsuchthat the lowered-ge oftheconnecting rod- 39 stillioccupies a posi-tion sub,- stantially in theplane occupied the upper surfaces of the blocks 31-When the latter' are'at the'upper end of the member 2.'v Y f Y 2 As indicated in'Fig. 4,theconnectingrod v v'39* functions, to retain the blocks 31 at theupper. Oendfof theinclined plane byengaging the; projectinghlds 36 f theboltsi', 'and thev bolts are preferably. ,so-'placed `in the Y blocks,that the forwardedges of the latter# .'i'vlien retained as describedlie, on a line lwith the4 Zr0, or initial. mark of thefcales on theASide niiesll]am?!VK 12 es Shows '11.1 g- 1- n ldepressing theconnectingrod- 4 1Y at the rear. end. l0i the links 381th@ AC01in"fiilared 3.9.:will be elevated tof release the bleeks- 31 vvardly on the planeysufficiently; far to Vbring the heads of theV bolts 36above the positionof the'rodf39, tohave the blocks automatically'retained atV the upperend'of f the plane until the rod 39 is elevated as described above.

On the base plate l and at the bottom of the member 2 is a stop element44 against which the blocks 31 impinge as they approach the bottom *offthe plane.

. It is obvious that the material of which the member 2 sfmade willaffect the action 0f the VVtest specimens on the plane. Where the'deviceis' usedto test leather belting it is desirable-to form thesurface` on Whichthe blocks slide of material or materials of whichpulleys are rcommonly frmed'and' to'have the surface conform as closelyas possible in physical characteristics to the pulley surface. There isto be no limitation as to thephysical characteristics of the surface ofthe member 2 on which-the blocks slide.

Preferably the ways 6, 7, and 8 are made of such VWidth that there. isno likelihood under normal conditions of the `blocks coming inlcontactwith the partition elements as theyslidedown the plane. In the otherinstances'it may. be desirable tor so form .the partition elements or.the blocks that if contact is made the area. thereof shall be a minimum.A l f l Y The operation of the device will,v be apparent from theforegoing description.l With the different test 'specimens 28 occupyingthe recesses in'fthe under faces of theblocks 31 `and the member 2elevatedV to the desired inclination, release ofthe blocks 31asfdescribed permits.themtoy move down the plane, and the dierent ratesof movement of the blocks, or the time required to.- pass down the`plane will aord an'accurateindieation ofthe frictional fcharacteristics of the respective; test specimens; or the. plane may belowered by manipulationi of the hand wheel 18,. and lwith thetestspecimensin position at the; upper fend `ofthe plane, the llatterymay be gradually elevated; note beingy ymade. of the respectiveangulanpositions. of the members 2 `atp which :the differenti. specimensstart moving down the planet In this-instance, of: course, .it will Vvbenecessary. to'. render inoperative4 the `blockretaining means; at.thewtop of the plane so that thespecimensarefree to move downthe plainewhen the inclination is such that, the frictional resistance of thespecimen is` over` fcone. The respective inclinations; of` the plane at.which the diiferent specimensprstart moving down t-he planeafford afurtherco'm- .parativ'eftest `of thee frictional characteristics ofv thesaid* specimens. Obviously the` device affords a 'meansA fork 'testingtheV frictional l A Y inertia ofi materials, that 'is the frictional re-:which are thenpernutted to movev dorm the inclined plane."Thearrangementais suclrthat it is -onlywneces'sary to slide.l the,blocks; up-

sistance': opposing'finiti'a'l movement when the body isy atrest,sometimes: called' static fric- I a friction-testing machine, the com-lbination with a base,of lamember pivotallyy l'lU secured at one end tothe base and constituting an adjustable inclined plane,` partitionelements dividing the plane into a plurality Y v of separate Ways7 meansfor vertically adjustof said pivot lying in the plane of the "uppersurface of said member, a specimen-holding block slidable on the saidupper surface of said member, means for vertically adjusting l the freeend of said plane member, andy a relatively fixed member on the basegrad-VA uated and adapted to cooperate with the said pivoted member togive an indication of the inclination thereof in any adjusted position.

CHAS. E. CARPENTER.

